Cardiac valve repair devices configured for percutaneous delivery

ABSTRACT

Disclosed herein are devices for improving coaption of the mitral valve leaflets to reduce or eliminate mitral valve regurgitation. The devices may be used to perform mitral valve annuloplasty, or to serve as a docking station for a transcatheter prosthetic heart valve. The various embodiments of devices are configured for percutaneous and, in some cases, transvascular delivery. Delivery systems useful for routing the devices to the mitral valve are also disclosed, including catheters, balloons and/or mechanical expansion systems. The devices themselves include at least one tissue penetrating member. Methods of delivery include partially embedding the devices in the mitral valve annulus via at least one tissue penetrating member. Tissue penetrating members may be embedded into the tissue in a simultaneous or a nearly simultaneous fashion. Upon embedding, the devices employ various expansion and/or contraction features to adjust the mitral valve diameter. Adjustments may continue until the leaflets fully coapt and the problem of mitral regurgitation is reduced or eliminated.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.15/167,760, filed May 27, 2016, claiming priority to U.S. ProvisionalApplication No. 62/169,395, filed Jun. 1, 2015, the contents of both ofwhich are incorporated herein by reference in their entireties.

BACKGROUND

The native heart valves (i.e., the aortic, pulmonary, tricuspid andmitral valves) serve critical functions in assuring the forward flow ofan adequate supply of blood through the cardiovascular system. Theseheart valves can be rendered less effective by congenital malformations,inflammatory processes, infectious conditions or disease.

Mitral valve regurgitation occurs when the posterior and anteriorleaflets fail to fully close during systole. This enables blood to leakbackward into the left atrium during contraction. The most common causeof mitral regurgitation is age-related connective tissue degeneration.Degenerative valve diseases occur at an annual incidence rate of 2-3% inindustrialized nations. Mitral regurgitation may also be caused bycardiac ischemia, cardiac dilation/remodeling, Rheumatic fever, Marfan'ssyndrome, and other diseases and disorders.

Such damage to the valves can result in serious cardiovascularcompromise or death. For many years the definitive treatment for suchdisorders was the surgical repair or replacement of the valve duringopen heart surgery. However, such surgeries are highly invasive and areprone to many complications. Therefore, elderly or frail patients withdefective heart valves often go untreated.

Minimally invasive, transvascular techniques now enable surgeons toaccess cardiac valves without open-heart surgery. Catheters are insertedinto vasculature at a site that is relatively distant from the heart.The catheters carry therapeutic devices through the patient'svasculature and to the malfunctioning heart valve. Once there, thedevices are deployed within the valve to prevent further backflow ofblood. For example, a transvascular technique has been developed forintroducing and implanting a prosthetic heart valve using a flexiblecatheter in a manner that is much less invasive than open heart surgery.In this technique, a prosthetic valve is mounted in a crimped state onthe end portion of a flexible catheter and advanced through a bloodvessel of the patient until the valve reaches the implantation site. Thevalve at the catheter tip is then expanded to its functional size at thesite of the defective native valve such as by inflating a balloon onwhich the valve is mounted.

Another known technique for implanting a prosthetic aortic valve is atransapical approach where a small incision is made in the chest wall ofa patient and the catheter is advanced through the apex (e.g., bottomtip) of the heart. Transapical techniques are disclosed in U.S. PatentApplication Publication No. 2007/0112422. Like the transvascularapproach, the transapical approach can include a balloon catheter havinga steering mechanism for delivering a balloon-expandable prostheticheart valve through an introducer to the aortic annulus. The ballooncatheter can include a deflecting segment just proximal to the distalballoon to facilitate positioning of the prosthetic heart valve in theproper orientation within the aortic annulus.

The above techniques and others have provided numerous options for highoperative risk patients with aortic valve disease to avoid theconsequences of open heart surgery and cardiopulmonary bypass. Whiledevices and procedures for the aortic valve are well developed, suchcatheter-based procedures are not necessarily applicable to the mitralvalve due to the distinct differences between the aortic and mitralvalve. The mitral valve has a complex subvalvular apparatus, i.e.,chordae tendineae, which are not present in the aortic valve.

Surgical mitral valve repair techniques (e.g., mitral annuloplasty) haveincreased in popularity due to their high success rates and clinicalimprovements noted after repair. In addition to the existing mitralvalve repair technologies, there are a number of new technologies aimedat making mitral valve repair a less invasive procedure. Thesetechnologies range from iterations of the Alfieri stitch procedure tocoronary sinus-based modifications of mitral anatomy to subvalvularapplications or ventricular remodeling devices, which would incidentallycorrect mitral regurgitation.

However, for mitral valve replacement, few less-invasive options areavailable. There are approximately 25,000 mitral valve replacements(MVR) each year in the United States. However, it is estimated that over300,000 patients who meet guidelines for treatment are denied treatmentbased on their age and/or co-morbidities. Thus, a need exists forminimally invasive techniques for replacing the mitral valve.

SUMMARY

Disclosed herein are implementations of mitral valve repair devices. Thedevices may be used to perform mitral valve annuloplasty, or to serve asa docking station for a transcatheter prosthetic heart valve. Thevarious embodiments of devices are configured for percutaneous and, insome cases, transvascular delivery. Delivery systems useful for routingthe devices to the mitral valve are also disclosed, including catheters,balloons and/or mechanical expansion systems. The devices themselvesinclude at least one tissue penetrating member. Methods of deliveryinclude partially embedding the devices in the mitral valve annulus viaat least one tissue penetrating member. Tissue penetrating members maybe embedded into the tissue in a simultaneous or nearly simultaneousfashion. Upon embedding, the devices employ various expansion and/orcontraction features to adjust the mitral valve diameter. Adjustmentsmay continue until the leaflets fully coapt and the problem of mitralregurgitation is reduced or eliminated.

Mitral valve regurgitation is used herein as an example of a valvulardisorder that may be addressed using the disclosed devices and methods.However, the disclosed devices and methods could be adapted for use withthe aortic valve, the pulmonic valve and/or the tricuspid valve.

Disclosed herein are devices for improving the function of a cardiacvalve. The devices may be used to perform mitral valve annuloplasty, orto serve as a docking station for a transcatheter prosthetic heartvalve. The various embodiments of devices are configured forpercutaneous and, in some cases, transvascular delivery. Deliverysystems useful for routing the devices to the mitral valve are alsodisclosed, including catheters, balloons and/or mechanical expansionsystems. The devices themselves may be circular in shape or non-circularin shape, and include at least one tissue penetrating member. Methods ofdelivery include partially embedding the devices in the mitral valveannulus via at least one tissue penetrating member. Tissue penetratingmembers are embedded into the tissue in a simultaneous or nearlysimultaneous fashion. Upon embedding, the devices employ variousexpansion and/or contraction features to adjust the mitral valvediameter. Adjustments may continue until the leaflets fully coapt andthe problem of mitral regurgitation is reduced or eliminated. In someimplementations, the devices may be used as a docking station for aprosthetic mitral valve.

In some implementations, a device for improving function of a cardiacvalve may include a frame configured to fit within a cardiac valve. Theframe includes a proximal portion, a distal portion, and an openingextending therebetween. The frame is collapsible to a first position andexpandable to a second position. In some implementations, the frame isat least partially formed from a shape memory material. In someimplementations, shape memory and non-shape memory portions alternatealong the perimeter of the frame.

The frame may include a pair of tissue penetrating members extendingfrom the proximal portion of the frame. The tissue penetrating membershave ends with tissue penetrating surfaces. In the first position, thetissue penetrating members are positioned such that the penetratingsurfaces of each pair of tissue penetrating members abut one another toform a blunt end. In the second position, the penetrating members ofeach pair of tissue penetrating members are spaced apart such that theirrespective penetrating surfaces are exposed. In some implementations,the tissue penetrating members include tissue fixation mechanisms.

In some implementations, the frame may include a spiral tissuepenetrating member. The method of percutaneous valve repair includesrotating the frame such that the spiral tissue penetrating memberpenetrates the tissue of the cardiac valve.

In some implementations, the frame includes a retrieval feature. Forexample, the retrieval feature may include a hole in the frame and asuture line running through the hole and connecting the frame to thecatheter.

In some implementations, the frame is configured to retract from thesecond position and pull together the penetrated tissue.

In some implementations, a cinching device radially surrounds the frameand is used to adjust the overall diameter of the frame.

In some implementations, a device may include a frame with a latticeextending between the proximal and distal portions. The lattice includesa first plurality of struts and a second plurality of struts. Each strutof the second plurality is operably connected to at least one strut ofthe first plurality via respective connection points. The lattice alsoincludes at least one expansion feature extending between at least twoconnection points. The expansion feature is configured to mechanicallyadjust positions of the connection points relative to one another. Forexample, the expansion feature may adjust the position of the connectionpoints along an axis parallel to the longitudinal axis extending betweenproximal and distal portions of the frame. The expansion feature mayinclude a tissue penetrating member.

Transcatheter delivery systems for the devices include a catheter fornavigating the device through the cardiovascular system of a subject. Insome implementations, delivery systems may include a plurality ofrotation members configured to mechanically operate the expansionfeatures of the device. In these implementations, a controller takesinputs from a user and operates the rotation members via a torque shaft.The rotation members couple to the expansion features and expand orcontract the device based on inputs from the controller.

In some implementations, the transcatheter delivery systems includes acatheter, an elongate balloon, and a frame. The elongate balloon isconfigured to be attached to the catheter via an opening at the proximalend of the balloon. In the inflated state, the balloon has a proximalportion with a first diameter and a distal portion with a seconddiameter larger than the first diameter. The frame includes a proximalend, a distal end, and at least one tissue penetrating member extendingfrom the frame. The frame surrounds at least a portion of the elongateballoon. When the elongate balloon is in the uninflated state, the frameis in a corresponding collapsed state. When the elongate balloon is inthe inflated state, the frame is expanded to an expanded state. Methodsof percutaneous valve repair includes navigating the uninflated elongateballoon and the collapsed frame through the cardiovascular system of asubject via the catheter, and positioning the elongate balloon and theframe within a cardiac valve of the subject. A gas or liquid is movedthrough the catheter and into the elongate balloon, causing the balloonto inflate and the frame to expand to the expanded state. A force maythen be applied to the catheter in a manner that causes the at least onetissue penetrating member of the frame to penetrate the valvular tissueof the subject. The elongate balloon is then deflated such that theframe remains attached to the valvular tissue, and the catheter andelongate balloon are removed from the subject.

Some methods of percutaneous valve repair may include positioning theelongate balloon such that the proximal portion of the balloon ispositioned between leaflets of the cardiac valve. In someimplementations, the frame surrounds a portion of the proximal portionof the balloon. In other implementations, the frame surrounds a portionof the distal portion of the balloon. The elongate balloon may include aplurality of friction elements for increasing friction between theelongate balloon and the frame.

Further disclosed are methods for replacing a native mitral valve. Themethods include advancing an expandable ring toward the mitral valve.The ring includes a collapsible and expandable frame. The frame includesa plurality of tissue penetrating members disposed along an exteriorsurface, and a plurality of protrusions along an inner surface. The ringis expanded such that the tissue penetrating members penetratesurrounding tissue within the mitral valve. The method further includesadvancing a prosthetic valve toward the mitral valve. The prostheticvalve includes a collapsible and expandable tubular stent formed withintercrossing bars, as well as a valvular structure mounted within thetubular stent. The prosthetic valve is radially expanded within thering, such that protrusions on the inner surface of the ring extendbetween intercrossing bars of the tubular stent. This secures theprosthetic valve to the ring, thereby anchoring the prosthetic valvewithin the native mitral valve.

In some implementations of the methods for replacing a native mitralvalve, a delivery catheter is advanced toward the mitral valve. Thedelivery catheter includes a prosthetic valve disposed along its distalend portion. The prosthetic valve includes a collapsible and expandabletubular stent formed with intercrossing bars and a valvular structuremounted within the tubular stent. The method further includes radiallyexpanding the prosthetic valve within the mitral valve and expanding aring within the prosthetic valve. The ring includes a plurality oftissue penetrating members disposed along an exterior surface. Thetissue penetrating members extend through the intercrossing bars of thetubular stent and penetrate surrounding tissue along the mitral valve,thereby securing the prosthetic valve to the native mitral valve.

DESCRIPTION OF DRAWINGS

FIG. 1 is a cross section of a heart demonstrating the position of thenative mitral valve. The mitral valve is in a closed position.

FIG. 2 is a cross section of a heart with the mitral valve in an openposition.

FIG. 3 is a schematic view of the native mitral valve anatomy showingthe mitral leaflets attached to the papillary muscles via the chordaetendineae.

FIG. 4 depicts the native mitral valve as viewed from the left atrium.

FIG. 5A is a side view of a device for mitral valve repair and acorresponding delivery system.

FIG. 5B is an enlarged view of the device shown in FIG. 5A.

FIG. 6A is an enlarged view of the tissue penetrating members of thedevice shown in FIG. 5A. The tissue penetrating members are in an openposition.

FIG. 6B is an enlarged view of the tissue penetrating members of thedevice shown in FIG. 5A. The tissue penetrating members are in a closedposition.

FIG. 7A is a side view of a device being expanded by a balloon within anative mitral valve. The device is made of a shape memory material.

FIG. 7B is a side view of the device of FIG. 7A after removal of theballoon. The device retracts back to its shape set position.

FIG. 8A depicts a device including alternating portions of shape memoryand non-shape memory materials.

FIG. 8B depicts the device of FIG. 8A with the shape memory portionsretracted back to the shape set position.

FIGS. 9A-F depict a method of delivering a mitral valve repair deviceusing a balloon with multiple diameters.

FIG. 10 depicts a device for mitral valve repair including a cinchingsystem for adjusting the diameter of the device.

FIG. 11A depicts a device for mitral valve repair. The device includes aspiral shaped tissue penetrating member.

FIG. 11B is an enlarged view of a portion of the device of FIG. 11A. Theenlarged view highlights the retrieval feature.

FIG. 12A depicts the collapsed device of FIG. 11A mounted onto anuninflated balloon.

FIG. 12B depicts the expanded device of FIG. 11A mounted onto aninflated balloon.

FIGS. 13A-F show a representative method of delivery for the deviceshown in FIG. 11A.

FIG. 14A shows a device for mitral valve repair in an expanded state.The device may be mechanically expanded or contracted via expansionfeatures.

FIG. 14B shows the device of FIG. 14A in a collapsed state.

FIG. 15A is an enlarged view of an expansion feature for a mechanicallycontrolled device for mitral valve repair depicting the mechanism ofexpansion.

FIG. 15B depicts the expansion feature of 15A as a tissue penetratingmember pierces the valvular tissue.

FIG. 15C is a top view of the devices depicted in FIGS. 14A-B and 15A-B.

FIG. 16A is a cross section of a device for mitral valve repair. Thedevice includes expansion features and separate tissue penetratingmembers.

FIG. 16B is a top view of the device of FIG. 16A.

FIG. 17 depicts a delivery system for a mechanically controllable devicefor mitral valve repair.

FIGS. 18A-C are views of the mitral valve from the left atrium duringdifferent stages of the valve repair procedure using the device of FIGS.16A-B.

FIG. 19A depicts a device for mitral valve repair to be used inconjunction with a transvascular prosthetic heart valve.

FIG. 19B is a side view of a transvascular heart valve secured to themitral valve tissue by the device of FIG. 19A.

FIG. 19C is a top view of the device of FIG. 19A.

FIG. 20 is an alternate implementation of a device for mitral valverepair to be used in conjunction with a transvascular prosthetic heartvalve.

FIG. 21 is an alternate implementation of a device for mitral valverepair to be used in conjunction with a transvascular prosthetic heartvalve.

DETAILED DESCRIPTION

The following description of certain examples of the medical apparatusshould not be used to limit the scope of the medical apparatus. Otherexamples, features, aspects, embodiments, and advantages of the medicalapparatus will become apparent to those skilled in the art from thefollowing description, which is by way of illustration, one of the bestmodes contemplated for carrying out the medical apparatus. As will berealized, the medical apparatus is capable of other different andobvious aspects, all without departing from the spirit of the medicalapparatus. For example, the devices and methods disclosed herein aredescribed in the context of mitral valve repair. However, the devicesand methods may also have use in other areas of the cardiac anatomy, forexample, the aortic valve, the pulmonary valve, and/or the tricuspidvalve. Accordingly, the drawings and descriptions should be regarded asillustrative in nature and not restrictive.

It should be appreciated that any patent, publication, or otherdisclosure material, in whole or in part, that is said to beincorporated by reference herein is incorporated herein only to theextent that the incorporated material does not conflict with existingdefinitions, statements, or other disclosure material set forth in thisdisclosure. As such, and to the extent necessary, the disclosure asexplicitly set forth herein supersedes any conflicting materialincorporated herein by reference. Any material, or portion thereof, thatis said to be incorporated by reference herein, but which conflicts withexisting definitions, statements, or other disclosure material set forthherein will only be incorporated to the extent that no conflict arisesbetween that incorporated material and the existing disclosure material.

The Human Heart

Relevant portions of the human heart are shown in FIGS. 1 and 2. Ahealthy heart has a generally conical shape that tapers to a lower apex38. The heart is four-chambered and comprises the left atrium 4, rightatrium 26, left ventricle 6, and right ventricle 28. The left and rightsides of the heart are separated by a wall generally referred to as theseptum 30. The native mitral valve 2 of the human heart connects theleft atrium 4 to the left ventricle 6. The mitral valve 2 has a verydifferent anatomy than other native heart valves, such as the aorticvalve 14.

The mitral valve 2 includes an annulus portion 8, which is an annularportion of the native valve tissue surrounding the mitral valve orifice,and a pair of cusps, or leaflets, 10, 12 extending downward from theannulus 8 into the left ventricle 6. The mitral valve annulus 8 can forma “D” shaped, oval, or otherwise out-of-round cross-sectional shapehaving major and minor axes. The anterior leaflet 10 can be larger thanthe posterior leaflet 12, as shown schematically in FIGS. 3-4 forming agenerally “C” shaped boundary between the abutting free edges of theleaflets when they are closed together.

Referring to FIG. 1, when operating properly, the anterior leaflet 10and the posterior leaflet 12 function together as a one-way valve toallow blood to flow only from the left atrium 4 to the left ventricle 6.The left atrium 4 receives oxygenated blood from the pulmonary veins 32.When the muscles of the left atrium 4 contract and the left ventricledilates, the oxygenated blood that is collected in the left atrium 4flows into the left ventricle 6. When the muscles of the left atrium 4relax and the muscles of the left ventricle 6 contract, the increasedblood pressure in the left ventricle urges the two leaflets together,thereby closing the one-way mitral valve so that blood cannot flow backto the left atrium and is instead expelled out of the left ventriclethrough the aortic valve 14.

To prevent the two leaflets 10, 12 from prolapsing under pressure andfolding back through the mitral annulus 8 toward the left atrium 4, aplurality of fibrous cords called chordae tendineae 16 tether theleaflets 10, 12 to papillary muscles in the left ventricle 6. Referringto FIGS. 3 and 4, chordae 16 are attached to and extend between thepostero-medial papillary muscle 22 and the postero-medial margins ofboth the anterior leaflet 10 and the posterior leaflet 12 (A1 and P1areas, respectively, as identified by Carpentier nomenclature).Similarly, chordae 16 are attached to and extend between theantero-lateral papillary muscle 24 and the antero-lateral margins ofboth the anterior leaflet 10 and the posterior leaflet 12 (A3 and P3areas, respectively, as identified by Carpentier nomenclature). Mitralvalve regurgitation occurs when the anterior and posterior leaflets 10,12 fail to fully close during systole. This enables blood to leakbackward into the left atrium 4 during contraction.

Devices for Transvascular Mitral Valve Repair

Disclosed herein are devices for improving coaption of the mitral valveleaflets 10, 12 to reduce or eliminate mitral valve regurgitation. Thedevices may be used to perform mitral valve annuloplasty, or to serve asa docking station for a transcatheter prosthetic heart valve. Thevarious embodiments of devices are configured for percutaneous and, insome cases, transvascular delivery. Delivery systems useful for routingthe devices to the mitral valve are also disclosed, including catheters,balloons and/or mechanical expansion systems. The devices themselvesinclude at least one tissue penetrating member. Methods of deliveryinclude partially embedding the devices in the mitral valve annulus viaat least one tissue penetrating member. Tissue penetrating members maybe embedded into the tissue in a simultaneous or nearly simultaneousfashion. Upon embedding, the devices employ various expansion and/orcontraction features to adjust the mitral valve diameter. Adjustmentsmay continue until the leaflets fully coapt and the problem of mitralregurgitation is reduced or eliminated.

As an example of one embodiment. FIG. 5A shows a side view of a mitralvalve undergoing treatment with an example mitral valve repair device 40and device delivery system 60. Device 40 may be used to perform mitralvalve annuloplasty, or to serve as a docking station for a transcatheterprosthetic heart valve. The frame 42 of the mitral valve repair devicemay have different implementations. In the embodiment of FIG. 5A, themitral valve repair device has a frame 42 that is ring-like when viewedfrom above. In other implementations, the frame 42 may be shaped to suitthe anatomy of the native mitral valve, or may create non-symmetricalconstriction of the mitral valve annulus. For example, someimplementations of the ring may be D-shaped when viewed from above. Thesides of frame 42 may be latticed, as in FIG. 5A. Alternatively, theframe could be spiral shaped or solid as disclosed in laterimplementations. The frame is collapsible to facilitate delivery throughthe delivery catheter 62 of the delivery system 60. Once the device 40is delivered to the proper surgical location, the balloon 64 is used toexpand the frame.

The frame 42 shown in FIG. 5A includes a distal portion 44 terminatingat a distal side and a proximal portion 46 terminating at a proximalside. During delivery, the distal portion 44 of the frame 42 ispositioned farther from the delivery catheter 62 than the proximalportion. An enlarged illustration of the frame 42 of the embodimentshown in FIG. 5A is shown in FIG. 5B. The frame 42 includes a firstseries of parallel strut portions 48 extending between proximal anddistal ends of the frame 42. The frame 42 also includes a second seriesof parallel strut portions 50. Each strut portion of the first seriescrosses at least one strut portion of the second series, meeting at aconnection point 49. The frame 42 defines an opening extending betweenits distal and proximal portions 44, 46 in the direction of a centrallongitudinal axis. The struts also define a plurality of quadrangularspaces 47 positioned around the frame 42 in the circumferentialdirection. The frame 42 is collapsible to facilitate delivery throughdelivery catheter 62 and expandable to be deployed within the mitralvalve using balloon 64.

As shown in FIG. 5B, tissue penetrating members 52 may extend from theproximal portion 46 of the frame. These serve to pierce the tissueand/or anchor the frame to the mitral valve annulus. The tissuepenetrating members 52 include at least one penetrating point and/orsurface configured to cut through tissue. In some embodiments, thetissue penetrating members may also include tissue fixation mechanismsto prevent dislodgement of the device once the tissue has been cut andthe tissue penetrating member is under the tissue. For example, tissuepenetrating members may take the forms of hooks, barbs, anchors, screws,or coil-shaped anchors. In alternative embodiments, the tissuepenetrating members 52 may flare outward from the frame 40 to betterengage the tissue. In some cases, outwardly flaring tissue penetratingmembers 52 may be made of a shape memory material, such that the tissuepenetrating members flare outwardly during expansion of the frame.

The tissue penetrating members 52 extending from the proximal portion 46of the frame shown in FIG. 5B are shown in expanded views in FIGS. 6A-B.Tissue penetrating members 52 include ends 54 with at least onepenetrating surface 56. As shown in FIG. 6A, tissue penetrating members52 may extend from the strut portions 48, 50 of the frame 42. When thestruts of the frame are collapsed, these penetrating surfaces arebrought together into an abutting relationship to blunt the end 54, asshown in FIG. 6B. This facilitates shielding of the penetrating surfaces56 during the delivery of the device. Once the device reaches the valveand is expanded, the penetrating surfaces 56 are exposed as shown inFIG. 6A. In some embodiments, the tissue penetrating members are forcedinto the mitral valve tissue by a proximal movement of the balloon 64.

The tissue penetrating members shown in FIGS. 6A-B also include tissuefixation mechanisms in the form of barbs 58. For the implementationshown in FIG. 5B, the barbs 58 extend away from the tissue engagementmember 52 at an angle and toward the frame 42. This prevents the tissueengagement members 52 from sliding backward within the tissue onceembedded. A tissue engagement member 52 may have one tissue fixationmechanism, or it may have a plurality of tissue fixation mechanisms.Though FIGS. 5 and 6 show tissue fixation mechanisms in the form ofbarbs 58, they may take other forms, including but not limited tospines, hooks, bumps, ridges, or layers of porous materials.

The devices disclosed herein may be made using a polymer or a metal. Forall embodiments described herein, some of the materials may beradio-opaque to assist in fluoroscopic monitoring. In some embodiments,portions of the mitral valve repair device may be formed of a shapememory material. Shape memory materials may include shape memorypolymers or shape memory metals. For example, the shape memory materialsmay be nickel-titanium alloys. The shape memory materials may be shapeset in a first position by, for example, heat conditioning. If thematerial is shape set by heat conditioning, it is then cooled. In thecooled state, it may be deformed to a second position. The secondposition is retained until a stimulus is applied, for example, heatingabove a critical temperature. The stimulus causes the shape memorymaterial to revert back to its first position. While heat conditioningis given as an example process used to set a shape memory material,other types of conditioning may be performed to achieve the samepurpose.

For example, a mitral valve repair device 40 may be shape set in afirst, collapsed position for moving through the patient's vascularsystem via delivery system 60. This provides a mechanism for securingthe valve to the balloon during delivery. The balloon 64 may then expandthe device 40 to a second position during deployment, as shown in FIG.7A. As shown in FIG. 7B, the shape memory material contracts to itsoriginal, first position after the balloon 64 is removed because bodytemperature is above the critical temperature for the particularmaterial. The frame thus exerts a continuous inward force, promotingcoaption of the leaflets 10, 12 and reducing or eliminating mitralregurgitation.

A shape memory device 40 that promotes an inward constrictive force maynot be optimal for all patients. For example, some disorders may causethe tissues of the mitral valve annulus 8 to weaken. In these cases, thetissue penetrating members 52 may be ripped out of the weakened annulartissue by the inwardly constrictive force. An alternative embodiment isa shape memory device 40 that is shape set in an expanded state. Thisdevice would open to its expanded state upon release from the deliverysystem 60, and would not contract after expansion. While it would notexert an inwardly constrictive force on the annulus, it could actagainst disease-related dilation of the annulus, slowing or preventingthe progression of the disease.

The embodiment depicted in FIGS. 8A and 8B is formed of alternatingshape memory and non-shape memory materials. A first set of strutportions 53 surrounding a quadrangular space 47 may be made of, forexample. Nitinol, as depicted by the unshaded strut portions in FIG. 8A.A second set of strut portions 55, depicted by the shaded strut portionsin FIG. 8A, may be made of a non-shape memory material such as stainlesssteel. FIG. 8B shows the device of FIG. 8A in its contracted state. Onlythe strut portions of shape memory material would contract afterexpansion. The embodiment of FIGS. 8A and 8B depicts alternating sets ofshape memory and non-shape memory struts. However, shape memory andnon-shape memory materials may be combined in other patterns withoutdeviating from the concept of the embodiment.

Alternative embodiments of the frame 42 may include non-uniformpatterning of the struts 48, 50. For example, the struts may vary intheir width, thickness and/or proximity to each other depending upontheir location on frame 42. Variability in strut patterning serves tocreate frames with different, non-circular shapes. For example, anon-uniform strut pattern may be designed that specifically places moreconstrictive force on a particular region of the mitral valve annulus 8.

An example delivery system is depicted in FIG. 9. The delivery system 60includes at least the following components; catheter 62, guide wire 66,and balloon 64. The balloon 64 may include portions with varyingdiameters. For example, the proximal portion 65 of the balloon 64depicted in FIGS. 5A and 9 is narrower than the distal portion 63.Alternatively, the balloon 64 may be tapered in shape such that theproximal portion 65 is narrower than the distal portion 63. In someembodiments, the surface of the balloon may include bumps, ridges,and/or other friction-increasing elements to prevent the device 40 fromslipping along the length of the balloon 64. The balloons may be formedof, for example, polyethylene terephthalate. Nylon, or a compositematerial. Other suitable materials may be used as well.

FIGS. 9A-F show an example method of delivering a mitral valve repairdevice. The methods of mitral valve repair disclosed herein may includea variety of approaches to reach the mitral valve including, forexample: transseptal, transapical, transfemoral, transatrial, and/ortransaortic approaches. The exemplary method of FIGS. 9A-F depict atransfemoral approach, wherein the device is tracked through the femoralartery and into the left ventricle. FIG. 9A shows a guide wire 66 thathas been threaded through the left ventricle, through the mitral valveannulus 8, and into the left atrium 4. A delivery catheter 62 containingthe mitral valve repair device 40 is run along the guide wire 66, asshown in FIG. 9B. The distal end of the catheter 62 is positioned withinthe left atrium 4, as shown in FIG. 9C. The catheter, in someembodiments, may employ similar bending mechanisms as those described inU.S. Pat. No. 7,780,723, which is hereby incorporated by reference inits entirety.

The balloon is positioned such that, upon inflation, its narrower,proximal portion 65 is between the leaflets 10, 12 of the mitral valve,as shown in FIG. 9D. The proximal portion 65 of balloon 64 serves tohold the native mitral valve in an optimal shape. The wider, distalportion 63 expands the device 40. The device 40 is positioned such thatthe tissue penetrating members 52 are approximately 1-5 mm from themitral valve leaflets. After the positioning of the device 40 isverified, the surgeon induces a proximal movement of the delivery system60. This proximal movement pulls the tissue penetrating members 52 ofthe device 40 into the mitral valve annulus 8 and/or the surroundingleaflet tissue. This causes the tissue penetrating members to beembedded into the tissue in a simultaneous or nearly simultaneousfashion. Once the device 40 is deemed secure, the balloon 64 may bedeflated and the delivery system 60 removed from the subject, as shownin FIGS. 9E-F. Rapid pacing may be used to ensure stable deployment ofthe implant and good engagement of the tissue penetrating members intothe tissue.

In method embodiments utilizing a shape memory frame 42 that is pre-setin an expanded state, the delivery system 60 may also include anadditional delivery sleeve placed around the frame 42. Once the frame 42is positioned above the mitral valve (in the left atrium 4), the sleeveis retracted to enable expansion of the frame into the pre-set, expandedstate. A balloon 64 may be included in the delivery system 60 of thisimplementation, at least in order to facilitate positioning of thedevice 40.

Other embodiments of the balloon 64 or alternative methods of using theballoon may be employed. For example, a tapered balloon with a widerdistal end 63 may help to push the tissue penetrating members into themitral valve annulus 8 when the surgeon induces a proximal movement ofthe delivery system 60. Alternatively, the balloon's diameter mayincrease in a step-wise fashion along its axis in a distal direction. Ineither case, when the surgeon induces a proximal movement, the widerwall of the distal-most portion of the balloon 64 abuts the frame topush the tissue penetrating members into the annular tissue 8.

In another embodiment, the device 40 may be expanded by a perfusionballoon or other expandable structure that, upon inflation, has a lumenthat enables blood to flow through the valve during the surgicalprocedure. This facilitates slow inflation and precise deployment of thetissue engagement members 52. A perfusion balloon may be deflatedslowly, or re-inflated if the tissue engagement members 52 are notproperly engaged with the tissue. In some implementations, methodsincorporating perfusion balloons may be performed without rapid pacingand under normal or close to normal hemodynamic conditions. In someimplementations, the perfusion balloon may also incorporate a tri-slitsleeve to function as temporary leaflets.

The devices 40 and/or delivery systems 60 may include additionalcomponents for adjusting the diameter of the mitral valve repair device40. For example, as seen in FIG. 10, the device may include adiameter-adjusting suture 57. The suture 57 may be threaded throughholes 71 in the frame 42. Alternatively, the suture 57 may be threadedthrough the voids formed between struts within the frame structure. Thecorresponding delivery system 60 may incorporate a cinching system 68which is deployed from the delivery catheter 62. For the embodimentshown in FIG. 10, the cinching system 68 includes a locking mechanism69, which secures the suture 57. The securement of the suture 57stabilizes the diameter of frame 42.

Some embodiments of mitral valve repair device may be spiral shaped, asin device 140 of FIGS. 11A and 11B. The device 140 shown in FIG. 11Aincludes a spiral shaped frame 142 having a distal portion 144, aproximal portion 146, and a tissue penetrating member 152 located on theproximal side of the proximal portion 146. The device 140 may alsoinclude at least one hole 141 for attaching a retrieval suture. Aportion of an example device 140 having two holes 141 is shown in FIG.11B.

FIG. 12A shows an example spiral-shaped device 140 in a collapsed statearound delivery balloon 164. A retrieval suture 143 attaches to theretrieval holes 141. The other end of the retrieval suture 143 may beattach to nose cone 161. Upon inflation of the balloon 164, the coil ofthe frame 142 is partially unwound. FIG. 12B shows the device 140 in anexpanded state upon an inflated balloon 164.

FIGS. 13A-F depict an example method for deploying the device 140 ofFIGS. 12A and 12B to the subject's mitral valve. This device is routedto the mitral valve area in a manner similar to that shown in FIG. 9A-F.Once the balloon 164 is inflated between the mitral valve, as shown inFIG. 13D, the shaft of the catheter 162 is rotated. This rotation drivesthe tissue penetrating member 152 (shown in FIG. 12B, for example) intothe mitral valve annulus 8. Continued rotation drives the device 140around the annulus, as shown in FIG. 13E.

In some rotated implementations, a hypotube may be slid over device 140after it has been embedded in the annulus (not shown). The hypotube maybe laser-cut or heat shaped, and could serve to further reshape theannulus. In other rotated implementations, the annulus 8 iscircumscribed by the hypotube before the device 140 is deployed. Oncethe hypotube is embedded, device 140 is tracked through the inner lumenof the larger hypotube, allowing for additional opportunities to reshapethe annulus. In some implementations, multiple hypotubes may be deployedover one another. Once the annulus 8 is circumscribed by device 140and/or the hypotube(s), the delivery system 160 is removed.

The mitral valve repair device 140 may be made of a metal or a polymer.In some embodiments, the device 140 is made of a shape memory material.For example, a shape memory mitral valve repair device 140 may be set ina collapsed state prior to deployment, then expanded by a balloon 164during deployment. After the embedding of the device 140 and removal ofthe delivery system 160, the device returns to its collapsed, coiledstate. This exerts an inwardly constrictive force on the annulus 8. Someembodiments may include electronic systems to facilitate remotemechanical adjustments to the shape of the device 140, similar to thosedescribed in U.S. Pat. Nos. 7,507,252 and 7,695,512, which are herebyincorporated by reference in their entireties. These remote adjustmentsmay be assisted by echocardiography, fluoroscopy, and the like.

FIG. 14A shows an example embodiment of a mechanically controllabledevice 240 for mitral valve repair. Device 240 may be used to performmitral valve annuloplasty, or to serve as a docking station for atranscatheter prosthetic heart valve. Device 240 includes a frame 242including a distal portion 244 and a proximal portion 246. The frameincludes a first series of struts 248 and a second series of parallelstruts 250. The first and second series of struts meet at connectionpoints 249. Strut connection points 249 are located at the proximal anddistal ends of frame 242, as well as at least one central location alongthe length of the frame. The device 240 may be urged into a collapsedstate, as shown in FIG. 14B. This collapsed state may allow, forexample, for delivery of the device 240 through a catheter to thesurgical site.

The embodiment of FIGS. 14A and 14B has an adjustable diameterfacilitated by at least one expansion feature 267. The expansionfeatures 267 may be mechanically controlled. An exemplary expansionfeature 267 is shown in detail in FIG. 15A. Expansion feature 267 has ascrew head 270 and a screw shaft 269 that is threaded through a firststrut connection point 249 on the distal portion 244 of the frame andinto a second strut connection point 249 on the proximal portion 246 ofthe frame. Rotation of the screw shaft 269 results in expansion orcollapse of the frame 242, depending on the direction of rotation. Asshown in FIG. 15B, the rotation of the screw shaft 269 helps to drivethe tissue penetrating member, 252, into the annular tissue 8. A topview of this embodiment, indicating the positioning of the expansionfeatures 267, is shown in FIG. 15C.

The material used to make the embodiment of device 240 shown in FIGS.14A-B and 15A-C may be a shape memory or non-shape memory material. Fora shape memory material, the frame 242 may be set in a collapsed stateprior to deployment. After deployment, the expansion features 267 serveto keep the frame open. For a non-shape memory material, the expansionfeatures 267 would serve to secure the frame 242 in its final state. Thepresence of expansion features 267 allows for a reduction in the amountof material used for the struts 248, 250 of the frame. The profile ofthe fully collapsed device 240 may be between 15-25 French, for example,20 French.

FIG. 16A shows an example embodiment of a device 240 having anothertissue penetrating member 352. In this example, the tissue penetratingmembers 352 are helical screws that extend through strut connectionpoints 249. FIG. 16B shows a top view of this embodiment, including theexpansion feature 267 screw heads 270 as well as the tops of the helicalscrew tissue penetrating members 352.

FIG. 17 shows an exemplary delivery system for a device such as theembodiments of device 240 shown in FIGS. 14-16. The system includes adelivery catheter 262 as well as a handheld control device 272 forcontrolling the expansion features 267 of the device 240. A torque shaftmechanism may be used to manipulate the expansion features 267 and/orthe tissue penetrating members 352. The torque shaft mechanism may bepartially housed within the delivery system 260. The torque shaftmechanism includes rotation members 274, and at least one motor thatdrives the rotation of the rotation members 274. The rotation members274 extend from the motor, through the delivery system 260 and out thedistal end of the delivery system 260. The rotation members 274 mayterminate in keys, for example, hex keys 276, that engage the screwheads 270 of expansion features 267. In some implementations, therotation members 274 may engage the ends of the tissue penetratingmembers 352. The motor of the torque shaft mechanism therefore drivesthe rotation of expansion features 267 and/or tissue penetrating members352 via the rotation members 274. In some implementations, a first motoris provided to induce rotation of the expansion features 267, and asecond motor is provided to induce rotation of the tissue penetratingmembers 352, such that expansion and tissue engagement may be separatelycontrolled.

The handheld device 272 shown in FIG. 17 may have separate control areasA, B for separating diameter adjustment controls from the tissueengagement controls. For example, control area A may operate a firstmotor of the torque shaft mechanism that drives rotation of theexpansion features 267. Control area B may operate a second motor of thetorque shaft mechanism that drives rotation of the tissue penetratingmembers 352. Therefore, control area A may be used to increase ordecrease the diameter of the device 240, while control area B may beused to move the device 240 in a manner that causes the device 240 toengage the patient's tissue in a desired location.

FIGS. 18A-C show an example embodiment of a device 240 being deployed onan annulus 8. FIG. 18A shows the annulus 8 prior to deployment of thedevice 240. As shown in FIG. 18B, the annulus 8 initially conforms tothe fully expanded frame 242. During this phase the annulus 8 mayinitially be expanded via a balloon or other expansion means. Next, theexpanded annulus 8 may be pierced by tissue penetrating members 252and/or 352. Helical screw tissue penetrating members 352 may bemechanically controlled to ensure tissue engagement. In someimplementations, the tissue penetrating members 252 and/or 352 may beembedded into the tissue in a simultaneous or nearly simultaneousfashion. Not every tissue penetrating member must penetrate the annulus8, however. In some embodiments, for example, only certain tissuepenetrating members may penetrate the annulus 8. Additionally oralternatively, the screw heads 270 of the expansion features 267 may beindividually tightened to customize the shape of the ring to thepatient's needs. These methods can be used to adjust the device 240 suchthat the mitral valve is repaired with improved precision. The implantmay be checked for mitral valve leaks during the procedure byechocardiography or similar methods to confirm the functionality of thedevice 240. FIG. 18C shows the device 240 after adjustments have beenmade to the shape of the frame 242.

The mechanically controlled device 240, delivery system 260, and methodof delivery have several advantages that may be useful for certainpatients or conditions. For example, the expansion features 267 can bemanipulated either individually or as a unit. Some of the expansionfeatures 267 may be tightened to a greater extent than others to createcustomized frame shapes, such as the one seen in FIG. 18. The helicalscrew tissue penetrating member 352 may be reversibly engaged to thetissue, allowing for adjustments if necessary. Finally, an additionaladvantage of the mechanically controlled embodiments described above isthat blood may continue to flow through the native valve duringdelivery.

FIG. 19A shows an example embodiment of a device 440 for percutaneousmitral valve repair. This embodiment may be used, for example, as adocking station for a transcatheter heart valve (THV). As shown in FIG.19A, the device 440 includes a frame 442 and tissue penetrating members452 extending outwardly from the frame. FIG. 19B shows the device 440 inuse as a docking station for a THV 480. The frame 442 may be solid asshown in FIG. 19A, or it may have a latticed structure as seen in FIG.19B. The device also may also include protrusions 478 extending inwardlyfrom the frame, as seen in FIG. 19A. The protrusions 478 may nest withinspaces along the outer wall of a THV 480 to secure the THV 480 to thedevice 440 and thus, to the surgical location. FIG. 19C is a top view ofthe THV 480 nested within the frame 442 of the device 440.

For the embodiment shown in FIGS. 19A-C, the THV 480 is secured to thedevice 440 by nesting the diamond-shaped protrusions 478 into spaces ofa latticed THV wall. However, protrusions 478 and corresponding spacesalong the wall of the THV 480 may take various shapes. For example, theprotrusions may be rods, bumps, ridges, or any configuration suitablefor nesting within corresponding spaces located on the wall of THV 480.

Device 440 shown in FIG. 19A includes tissue engagement members 452 forsecuring the frame 442 to the tissue. In some embodiments, the force ofexpansion of the THV 480 drives the tissue engagement members 452 of thedevice 440 into the tissue such that the expansion of the THV 480 andthe device 440 may be performed simultaneously. In other embodiments,the device 440 may be first secured to the annular tissue 8 usingstaples, sutures, fabric, a porous tissue fixation layer, or anothersecuring mechanism. The THV 480 may then be expanded within the device440 after the device 440 is secured to the tissue

FIG. 20 shows an example embodiment of a device 440 that is similar tothe one shown in FIGS. 19A and 19B, but lacks internal protrusions. Forthis embodiment, the THV 480 is deployed first to the native mitralvalve. Device 440 is then opened within the lumen of the THV 480. Tissuepenetrating members 452 pierce the wall of the THV 480 and secure it tothe mitral valve annulus 8. The wall of THVs 480 used in conjunctionwith this embodiment may include of a material, such as a fabriccovering, that can be punctured by the tissue penetrating members 452.

FIG. 21 shows another example embodiment of a device 540 for mitralvalve repair. Like the embodiments of FIGS. 19 and 20, device 540 may beused as a docking station for THV 480. Device 540 also includes a frame542. Extending outwardly from the frame is a knob 582 for limitingmovement of the device 540 during the procedure. Some implementationsmay include multiple knobs positioned in different locations of frame542. Tissue penetrating members 552 protrude outwardly from the knob582. In some embodiments, the tissue penetration members 552 may alsoinclude tissue fixation mechanisms, such as barbs 558. Barbs 558 extendaway from the tissue penetrating members 552 at an angle, creating aphysical barrier to slippage of the tissue penetrating members 552within the tissue once embedded.

In one example, device 540 shown in FIG. 21 may be deployedtransseptally prior to the deployment of the THV 480. The device 540 maybe made of a shape memory material and expand above the mitral valveannulus 8 once released from the delivery catheter. During expansion,the tissue penetrating members 552 pierce the tissue of the mitral valveannulus 8. The device may then be further stapled or sutured to themitral valve annulus 8 prior to delivery of the THV 480. Knob 582 andtissue penetrating members 552 limit movement of the frame 542 duringsubsequent stapling or suturing. Once the device 540 is secured to theannulus, it may be used to anchor the THV 480 to the native mitralvalve.

For each of the embodiments in FIGS. 19-21, the devices 440, 540 and THV480 may be delivered by a single catheter (in series), or by a separatecatheter. They could be delivered from the same direction (transseptal,transapical, transfemoral, transatrial, transaortic), or from differentdirections. For the embodiment of FIG. 20, device 440 is deployed withinthe THV at a location that will not penetrate the prosthetic leaflets ofthe THV 480. THVs 480 used in conjunction with these embodiments mayinclude structures for mating with the devices 440, 540. For example,THV 480 may include a flange for mating with the ring, thereby avoidingdamage to the prosthetic valve structure.

THVs 480 to be used in mitral valve repair may have a shape thatconforms to the mitral valve. For example, the wall of the THV may becurved and of different dimensions than THVs useful for other cardiacheart valves. Some embodiments of the methods may include devices formitral valve repair that cooperate with THV 480 by means other than thedevices disclosed above (e.g., 40, 140, 240, 340, 440, 540). Forexample, one or more fasteners may be used to secure the prostheticvalve directly to the mitral valve annulus 8 or to the leaflets 10, 12.The fasteners may be rivets, staples, or the like.

Although the disclosure has been shown and described with respect to acertain embodiment or embodiments, it is obvious that equivalentalterations and modifications will occur to others skilled in the artupon the reading and understanding of this specification and the annexeddrawings. In particular regard to the various functions performed by theabove described elements (components, assemblies, devices, compositions,etc.), the terms (including a reference to a “means”) used to describesuch elements are intended to correspond, unless otherwise indicated, toany element which performs the specified function of the describedelement (i.e., that is functionally equivalent), even though notstructurally equivalent to the disclosed structure which performs thefunction in the herein illustrated exemplary embodiment or embodiments.In addition, while a particular feature of the disclosure may have beendescribed above with respect to only one or more of several illustratedembodiments, such feature may be combined with one or more otherfeatures of the other embodiments, as may be desired and advantageousfor any given or particular application.

What is claimed is:
 1. A method for replacing a native mitral valve,comprising: advancing an expandable ring toward the mitral valve, thering comprising a collapsible and expandable frame comprising aplurality of tissue penetrating members disposed along an exteriorsurface of the ring and a plurality of protrusions along an innersurface of the ring; expanding the ring such that the tissue penetratingmembers penetrate surrounding tissue within the mitral valve; advancinga prosthetic valve toward the mitral valve, the prosthetic valvecomprising a collapsible and expandable tubular stent formed withintercrossing bars and a valvular structure mounted within the tubularstent; and radially expanding the prosthetic valve within the ring;wherein the protrusions on the inner surface of the ring extend betweenintercrossing bars of the tubular stent and secure the prosthetic valveto the ring, thereby anchoring the prosthetic valve within the nativemitral valve.
 2. The method of claim 1, wherein the ring comprises acircumferentially continuous ring frame during the acts of advancing thering and expanding the ring.
 3. The method of claim 1, wherein the ringcomprises an expandable frame which has a lattice structure.
 4. Themethod of claim 1, wherein the ring comprises an expandable frame whichhas a solid structure.
 5. The method of claim 1, wherein the pluralityof protrusions are juxtaposed with respect to the plurality of tissuepenetrating members along a circumference of the ring so that eachprotrusion is circumferentially positioned between two adjacent tissuepenetrating members and each tissue penetrating member iscircumferentially positioned between two protrusions.
 6. The method ofclaim 1, wherein radially expanding the prosthetic valve within the ringcauses the ring to radially expand so that radial expansion of theprosthetic valve and the ring are performed simultaneously.
 7. Themethod of claim 1, wherein radially expanding the prosthetic valvewithin the ring is performed after securing the ring to the surroundingtissue within the mitral valve.
 8. The method of claim 1, whereinadvancing the ring and advancing the prosthetic valve are performedusing a single catheter.
 9. The method of claim 1, wherein advancing thering and advancing the prosthetic valve are performed using two separatecatheters.
 10. The method of claim 1, wherein the ring and theprosthetic valve are advanced to the mitral valve from a same deliverydirection.
 11. The method of claim 1, wherein the ring and theprosthetic valve are advanced to the mitral valve from differentdelivery directions.
 12. The method of claim 1, wherein the plurality ofprotrusions are diamond-shaped.
 13. A method for replacing a nativemitral valve, comprising: advancing a delivery catheter toward themitral valve, the delivery catheter comprising a prosthetic valvedisposed along a distal end portion, the prosthetic valve comprising acollapsible and expandable tubular stent formed with intercrossing barsand a valvular structure mounted within the tubular stent; radiallyexpanding the prosthetic valve within the mitral valve; and expanding aring within a lumen of the prosthetic valve, the ring comprising aplurality of tissue penetrating members disposed along an exteriorsurface; wherein the tissue penetrating members extend through theintercrossing bars of the tubular stent and penetrate surrounding tissuealong the mitral valve, thereby securing the prosthetic valve to thenative mitral valve.
 14. The method of claim 13, wherein the ringcomprises an expandable, circumferentially continuous frame.
 15. Themethod of claim 13, wherein the ring comprises an expandable frame whichhas a lattice or solid structure.
 16. The method of claim 13, whereinthe ring is configured to mate with a flange of the prosthetic valve.17. The method of claim 13, wherein the tissue penetrating members arepositioned to penetrate a fabric covering of the prosthetic valve. 18.The method of claim 13, wherein a frame of the ring is configured topress against an inner surface of the prosthetic valve after expandingthe ring within the lumen of the prosthetic valve.
 19. The method ofclaim 13, wherein the plurality of tissue penetrating members aredisposed uniformly along the exterior surface of the ring.
 20. Themethod of claim 13, wherein the plurality of tissue penetrating membersare positioned to avoid penetrating the valvular structure.